Process for producing glass roll with a separable protective sheet

ABSTRACT

A manufacturing method for a glass roll includes forming a glass film by a downdraw method, winding the glass film into a roll using a winding roller in a state in which front and back glass surfaces of the glass film formed in said forming operation are exposed, and during said winding operation, superposing the glass film on a separable protective sheet. The protective sheet extends beyond both sides in a width direction of the glass film. The method may further include winding the protective sheet on an outer peripheral surface of the glass film by winding only the protective sheet from a trailing end of the glass film in a winding direction of the glass film.

TECHNICAL FIELD

The present invention relates to an improved technology for a packageform for a glass film which is used as a glass substrate for a flatpanel display and a solar cell, and used as cover glass or the like foran organic light-emitting diode (OLED) lighting.

BACKGROUND ART

In view of space saving, in recent years, there is widely used a flatpanel display, such as a liquid crystal display, a plasma display, anorganic light-emitting diode (OLED) display, or a field emissiondisplay, in place of a cathode ray tube (CRT) display that has beenconventionally and widely used. Such a flat panel display is required tobe further thinned. In particular, the OLED display is required to alloweasy carrying by being folded or wound, and to allow use not only on aflat surface but also on a curved surface. Further, uses on both flatsurfaces and curved surfaces are not limited to only display devices.For example, it is also required to form a solar cell or an OLEDlighting, on a surface of a product having a curved surface, such as asurface of a vehicle body of an automobile or a roof, a pillar, or anouter wall of a building. Therefore, various glass plates including theflat panel display are required to be further thinned for satisfying ademand for flexibility high enough to deal with a curved surface. Asdisclosed, for example, in Patent Literature 1, a film-like sheet glasshaving a thickness of 200 μm or less has been developed.

Meanwhile, in view of ensuring flexibility, a resin film may be used inplace of a glass plate. However, there is a problem in that the resinfilm is inferior to the glass plate in gas barrier property. In a caseof the OLED display, a light-emitting body to be used is deteriorateddue to contact with gas, such as oxygen or water vapor, and hence theresin film inferior in barrier property cannot be used in place of theglass plate. Further, for the same reason, also in a field other thanthe OLED display, the resin film cannot be used in place of the glassplate in many cases. Therefore, also in view of ensuring the barrierproperty described above, thinning of the glass plate takes onincreasing importance in actual use.

However, when the glass plate is thinned into a film, i.e., a so-calledglass film, breakage is more liable to occur. Consequently, a packageform used for transportation or the like becomes a major issue.Specifically, as a package form for a glass plate, there are known apackage form (see Patent Literature 2, for example) in which glassplates and protective sheets are packaged while being alternatelypropped at a predetermined angle on a pallet including a back surfaceportion, and a package form (see Patent Literature 3, for example) inwhich glass plates and protective sheets are packaged while beingalternately and horizontally stacked on a pallet. However, when theabove-mentioned package forms are adopted to the glass film, thefollowing problems arise.

That is, when adopting the former package form, there is a problem inthat it is extremely difficult to maintain a posture in the proppedstate due to flexibility of the glass film. Further, even if the glassfilm can be propped, there is a problem in that the glass film easilybreaks due to its extreme bending or concentration of stress applied ona very fragile lower end portion of the glass film.

In contrast, when adopting the latter package form, load of all glassfilms situated on an upper side is applied to glass films situated on alower side, and hence there is a problem in that the glass filmssituated on the lower side easily break.

Note that, when glass films are packaged while being stacked inhorizontal postures in an up-and-down direction, as disclosed, forexample, in Patent Literature 4, there may be adopted a package form inwhich glass plates are stacked in the up-and-down direction atintervals. However, in this package form, the glass films need to beplaced so that the glass plates are placed in a straddling manner on aplurality of support members arranged in parallel in a horizontaldirection at intervals, and hence the package form is not suitable forpackaging the glass film having flexibility. That is, the glass film hasflexibility, and hence it is difficult to place the glass film in astraddling manner on the support members, and placing of the glass filmforces a complicated operation. Further, even if the glass film can beplaced, all load of the glass film is supported only by contact portionswith the support members, and hence stress is concentrated on thesupported portions so that the glass film may break. Further, the glassfilm is bent downward due to its self-weight, and hence the glass filmsituated on the upper side may be held in direct contact with the glassfilm situated on the lower side, to thereby cause breakage.

Therefore, for the package form for a glass film, it is desired todevelop a unique package form for a glass film, which is different fromconventional package forms for a relatively thick glass plate. In thiscontext, for example, Patent Literature 5 discloses a new package formin which a composite film is wound into a roll together with anintermediate layer, the composite film including a glass film and apolymer layer coated on an entire one-side surface of the glass film.This package form is made focusing on flexibility of the glass film, andmay be effective as the package form for a glass film.

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2008-133174 A-   Patent Literature 2: JP 2005-231657 A-   Patent Literature 3: JP 2006-264786 A-   Patent Literature 4: JP 2005-75433 A-   Patent Literature 5: JP 2002-534305 A

SUMMARY OF INVENTION Technical Problem

By the way, in the composite film disclosed in Patent Literature 5, thepolymer layer is formed on the entire one-side surface of the glassfilm. This aims at prevention of breakage of the glass film. Further,the polymer layer is formed just before winding of the composite film.Specifically, after forming of the glass film, while the glass film isconveyed in a horizontal posture, polymer is applied on an upper surfaceof the glass film. Then, the polymer is irradiated with ultraviolet raysin a downstream step to cure the polymer, and the polymer is dried in adrying line, to thereby form the polymer layer.

However, when the polymer layer is formed on the surface of the glassfilm as described above, a large number of steps are necessary, such asthe above-mentioned application of the polymer. Consequently, not onlyare the steps complicated, but an entire length of the steps is alsoextremely extended only for formation of the polymer layer. As a result,there is increased a risk in that foreign matters adhere to the surfaceof the glass film, and hence it is difficult to ensure cleanness of thesurface of the glass film.

Further, after curing and drying the polymer layer formed on the surfaceof the glass film, the composite film is wound. Thus, in a case wherethe polymer layer is not completely cured at the winding stage, thepolymer layer may stick to the intermediate layer. In a case ofoccurrence of the stickiness, when unpackaging the composite film woundinto a roll, there is a fear in that the intermediate layer and thepolymer layer cannot be easily separated from each other, or the glassfilm breaks when performing forcible separation.

In addition, the glass film is rarely incorporated into an end productsuch as a flat panel display while remaining in a state of the compositefilm including the polymer layer formed on the glass film. Usually, itis necessary to remove the polymer layer in advance before incorporationinto the end product. In this case, after unpackaging the composite filmwound into a roll, it is necessary to provide an additional step forremoving the polymer layer, which becomes a factor in an increase inmanufacturing cost similarly to the forming step for the polymer layer.Moreover, when the polymer layer is not satisfactorily removed, theresidual polymer layer may serve as foreign matters on the surface ofthe glass film, which may lead to a big problem such as degradation invalue of the end product incorporating the glass film and degradation infunction.

Therefore, the package form disclosed in Patent Literature 5 also hasthe above-mentioned problems, and is still susceptible to improvement.

In view of the above-mentioned circumstances, it is a technical objectof the present invention to provide a package form, in which cleannessof a glass film is ensured and the glass film is prevented frombreaking. The package form is effective in minimizing the number ofglass film processing steps to be performed before packaging and afterunpackaging.

Solution to Problem

The present invention, which has been made to solve the above-mentionedproblems, provides a glass roll, which is formed by winding a glass filminto a roll while superposing the glass film on a protective sheet, theglass film being formed by a downdraw method and having exposed frontand back surfaces.

With this configuration, the glass film having the exposed front andback surfaces, which is formed by the downdraw method, is wound into aroll as it is together with the protective sheet, to thereby form theglass roll. Thus, in a step before packaging, it is unnecessary toperform, on both of the front and back surfaces of the glass film, alayer-forming step of forming a protective layer such as a polymerlayer. Also in a step after unpackaging, it is unnecessary to perform aremoving step of removing the protective layer such as the polymer layerfrom a surface of the glass film. Therefore, it is possible to reduce alength of the step before packaging by reducing length corresponding toa length of the step for forming the protective layer. Thus, an adhesionrate of foreign matters to the front and back surfaces of the glass filmcan be reduced as much as possible, and no foreign matters resultingfrom the protective layer remain after unpackaging. As a result, it ispossible to satisfactorily maintain cleanness of the front and backsurfaces of the glass film formed by the downdraw method. In addition,unlike ones formed by a float method, the front and back surfaces formedby the downdraw method are advantageous in ensuring cleanness in anunpolished state without performing ex-post surface polishing on theglass film.

Further, in a state of the glass roll, the exposed front and backsurfaces of the glass film are protected with the protective sheet.Moreover, the front and back surfaces of the glass film are glasssurfaces without the protective layer such as the polymer layer, andhence the glass film and the protective sheet are less likely to stickto each other at a winding stage. Therefore, it is possible to reliablyreduce breakage of the glass film in the state of the glass roll, and tosatisfactorily maintain separability between the glass film and theprotective sheet. Accordingly, breakage of the glass film at the time ofunpackaging can be reduced as much as possible.

Note that, even if the glass film is kept in a wound state for a longperiod of time, no warpage is generated, and hence the glass film can beeasily sent into a subsequent step. In addition, owing to winding, theglass film as a long product can be used, and hence the glass film canbe cut into a free length afterward, and can correspond to substrateswith various sizes. Consequently, it is possible to prevent waste of theglass film.

In the above-mentioned configuration, it is preferred that the glassfilm have a thickness of 1 μm or more and 200 μm or less.

With this, appropriate flexibility is imparted to the glass film. Thus,it is possible to alleviate overstress applied to the glass film whenthe glass film is wound, and to prevent the glass film from breaking.

In the above-mentioned configuration, it is preferred that each endsurface in a width direction of the glass film have an arithmeticaverage roughness Ra of 0.1 μm or less. Here, the “arithmetic averageroughness Ra” is a value measured with reference to JIS B0601:2001.

With this, appropriate smoothness is imparted to the each end surface inthe width direction of the glass film. Thus, when winding the glass filminto a roll, small flaws are less likely to occur on the each endsurface of the glass film, and hence it is possible to prevent breakageof the glass film from the each end surface. Therefore, it is possibleto reduce glass powder (cullet) generated due to chips resulting fromthe small flaws on the end surface of the glass film, which is veryadvantageous in ensuring cleanness of the front and back surfaces of theglass film. Further, even in a case where the end surface of the glassfilm is held in contact with the protective sheet, the end surface ofthe glass film does not bite into and scratch the protective sheet, andhence satisfactory separability between the glass film and theprotective sheet can be obtained.

In the above-mentioned configuration, it is preferred that the each endsurface in the width direction of the glass film include a cut surfacewhich is cut by laser cutting. Note that, the laser cutting describedherein includes laser splitting besides laser fusing.

With this, without performing post-processing such as polishing,appropriate smoothness can be easily imparted to the cut surfaceconstituting the each end surface in the width direction of the glassfilm. Thus, when winding the glass film into a roll, chips resultingfrom small flaws are less likely to occur on the each end surface of theglass film. Therefore, it is possible to reduce glass powder generateddue to the chips on the end surface of the glass film, which is veryadvantageous in ensuring cleanness of the front and back surfaces of theglass film. Further, even in the case where the end surface of the glassfilm is held in contact with the protective sheet, the end surface ofthe glass film does not bite into the protective sheet, and hencesatisfactory separability between the glass film and the protectivesheet can be maintained.

In the above-mentioned configuration, the protective sheet may extendbeyond both sides in the width direction of the glass film.

With this, the each end surface in the width direction of the glass filmcan be protected with the protective sheet. Further, each end in thewidth direction of the glass film is covered with the protective sheet,and hence it is also possible to prevent intrusion of foreign mattersfrom an outside.

In the above-mentioned configuration, it is preferred that theprotective sheet serve as an outermost layer.

With this, in the state of the glass roll, the glass film is not exposedat the outermost layer, and hence this is preferred also in view ofpreventing breakage of the glass film. That is, even when another membersuch as another glass roll comes into contact with the outermost layerof the glass roll, the outermost layer of the glass roll is covered withthe protective sheet, and hence the glass film is less likely to break(i.e., have flaws or cracks) directly. Further, the outermost layer isprotected with the protective sheet, which is advantageous in ensuringcleanness of the glass film.

In the above-mentioned configuration, it is preferred that theprotective sheet serve as an innermost layer.

With this, in the state of the glass roll, the glass film is not exposedat the innermost layer, and hence this is preferred also in view ofpreventing breakage of the glass film. Specifically, for example, evenin a case where the glass film is wound into a roll with use of a rollcore, the glass film and the roll core are not held in direct contactwith each other. Further, even in a case where the roll core is removedfrom a center of the glass roll, or the roll core needs to be insertedinto the center of the glass roll afterward, the protective sheet isinterposed between the glass film and the roll core, and hence thesurface of the glass film is less likely to break (i.e., have flaws) bybeing rubbed against the roll core.

In the above-mentioned configuration, the protective sheet may be formedof a resin sheet.

With this, cushioning performance of the protective sheet is improved,which is advantageous in reducing breakage of the glass film.

In this case, when the protective sheet is formed of a foamed resinsheet, more satisfactory cushioning performance is obtained, and hencethis is more preferred in view of reducing breakage of the glass film.

The present invention, which has been made to solve the above-mentionedproblems, provides a manufacturing device for a glass roll, including: aforming section for forming a glass film by a downdraw method; and awinding roller for winding the glass film while superposing the glassfilm on a protective sheet. The manufacturing device has a configurationin which the winding roller winds the glass film while superposing theglass film on the protective sheet under a state in which front and backsurfaces of the glass film are exposed.

With this configuration, it is possible to obtain the same action andeffect as those of the above-mentioned corresponding configuration.

In the above-mentioned configuration, it is preferred that themanufacturing device for a glass roll further include cutting means forlaser cutting a disused portion on a conveyance path ranging from theforming section to the winding roller, the disused portion being formedon each end portion in a width direction of the glass film.

With this, it is possible to obtain the same action and effect as thoseof the above-mentioned corresponding configuration.

In the above-mentioned configuration, the winding roller may be arrangedat a position shifted laterally from a position directly below theforming section, and the glass film drawn out of the forming section maybe curved and supplied to the winding roller arranged at the positionshifted laterally.

With this, at a position other than the position directly below theforming section, it is possible to perform a winding operation under astate in which a posture of the glass film has been changed from avertical posture to a horizontal posture.

In this case, it is preferred that an angle formed by a tangent linealong the glass film drawn out of the forming section, and a tangentline along the glass film at a contact point between the winding rollerand the glass film be 90 degrees or more, and that the glass film drawnout of the forming section be smoothly curved along the two tangentlines.

With this, it is possible to curve the glass film without causingoverstress to act on the glass film. Therefore, during the windingoperation for the glass film, the glass film is less likely to breakfrom its curved portion, and hence it is possible to continue the stablewinding operation.

The present invention, which has been made to solve the above-mentionedproblems, provides a manufacturing method for a glass roll, including:forming a glass film by a downdraw method; and winding, by a windingroller, the glass film into a roll while superposing the glass film on aprotective sheet under a state in which front and back surfaces of theglass film thus formed are exposed, to thereby form a glass roll.

According to this method, it is possible to obtain the same action andeffect as those of the above-mentioned corresponding configuration.

In the above-mentioned method, it is preferred to laser cut a disusedportion before a stage of winding the glass film by the winding roller,the disused portion being formed on each end portion in a widthdirection of the glass film.

According to this method, it is possible to obtain the same action andeffect as those of the above-mentioned corresponding configuration.

In the above-mentioned method, the glass film and the protective sheetmay be wound under a state in which the protective sheet is arranged onthe winding roller side relative to the glass film, and only theprotective sheet may be wound from a trailing end in a winding directionof the glass film so that the protective sheet is wound on an outerperipheral surface of the glass film.

With this, even when the glass film and the protective sheet are woundunder the state in which the protective sheet is arranged on the windingroller side relative to the glass film, in other words, under a state inwhich the protective sheet is superposed on an inner circumferentialside of the glass film at the time of winding, the outermost layer ofthe glass roll can be constituted by the protective sheet.

In the above-mentioned method, the glass film and the protective sheetmay be wound under a state in which the glass film is arranged on thewinding roller side relative to the protective sheet.

With this, when the protective sheet and the glass film are wound whilebeing superposed on each other, the outermost layer of the glass roll isautomatically constituted by the protective sheet, and hence it isunnecessary to wind only the protective sheet additionally after windingthe glass film.

In the above description, the downdraw method includes a slot downdrawmethod, an overflow downdraw method, and a redraw method. The overflowdowndraw method and the redraw method are advantageous in being able toform a glass film excellent in surface smoothness without performingadditional processing after the forming. Therefore, it is preferred thatthe overflow downdraw method or the redraw method be used as thedowndraw method.

Advantageous Effects of Invention

According to the present invention described above, it is possible toprovide, as a package form of a glass film, a glass roll with whichcleanness of the glass film is ensured and the glass film is preventedfrom breaking. The glass roll is effective in minimizing the number ofglass film processing steps to be performed before packaging and afterunpackaging.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A perspective view of a glass roll according to the presentinvention.

FIG. 2 An explanatory diagram of a manufacturing device for a glassfilm.

FIG. 3( a) A view illustrating a mode of providing a holding portion toa roll core, and illustrating a mode of holding the glass film and aprotective sheet.

FIG. 3( b) A view illustrating a mode of providing the holding portionto the roll core, and illustrating a mode of holding only the glassfilm.

FIG. 4 A view illustrating a mode in which an outer cylinder of the rollcore expands and contracts.

FIG. 5 An explanatory diagram of a manufacturing device for a glass rollaccording to the present invention.

FIG. 6 An explanatory diagram illustrating a method of applying heat oflaser irradiation onto the glass film and splitting the glass film usingthermal stress caused by the heat.

FIG. 7( a) A view illustrating a preferred cutting method for the glassfilm according to the present invention, and illustrating a state inwhich a scribe line passes pre-cutting rollers.

FIG. 7( b) A view illustrating a preferred cutting method for the glassfilm according to the present invention, and illustrating a state inwhich bend-breaking is performed.

FIG. 7( c) A view illustrating a preferred cutting method for the glassfilm according to the present invention, and illustrating a state inwhich a post-cutting end portion passes post-cutting rollers.

FIG. 8 A perspective view illustrating a mode of providing an outercovering body to the glass roll according to the present invention.

FIG. 9 A perspective view illustrating a mode of providing a support barto the roll core of the glass roll according to the present invention.

FIG. 10 A perspective view illustrating a mode of providing flanges tothe roll core of the glass roll according to the present invention.

FIG. 11 An explanatory diagram illustrating a method of placing theglass roll according to the present invention in a longitudinaldirection.

FIG. 12 A view illustrating a processing method for the glass rollaccording to the present invention.

FIG. 13 A view illustrating another processing method for the glass rollaccording to the present invention.

FIG. 14 A view of the protective sheet having a surface subjected toembossing.

DESCRIPTION OF EMBODIMENT

In the following, a glass roll and a manufacturing method for a glassroll according to a preferred embodiment of the present invention aredescribed with reference to the drawings.

FIG. 1 is a perspective view of the glass roll according to the presentinvention. FIG. 2 is an explanatory diagram of a manufacturing devicefor a glass film. FIG. 3 are views each illustrating a mode of providinga holding portion to a roll core, in which Part (a) is a viewillustrating a mode of holding the glass film and a protective sheet,and Part (b) is a view illustrating a mode of holding only the glassfilm. FIG. 4 is a view illustrating a mode in which an outer cylinder ofthe roll core expands and contracts. FIG. 5 is an explanatory diagram ofa manufacturing device for a glass roll according to the presentinvention. FIG. 6 is an explanatory diagram illustrating a method ofapplying heat of laser irradiation onto the glass film and splitting theglass film using thermal stress caused by the heat. FIG. 7 are viewseach illustrating a preferred cutting method for the glass filmaccording to the present invention, in which Part (a) is a viewillustrating a state in which a scribe line passes pre-cutting rollers,Part (b) is a view illustrating a state in which bend-breaking isperformed, and Part (c) is a view illustrating a state in which apost-cutting end portion passes post-cutting rollers.

As illustrated in FIG. 1, a glass roll (1) according to the presentinvention is obtained by superposing a glass film (2) onto a protectivesheet (3) and winding the glass film and the protective sheet into aroll, the glass film being formed by a downdraw method and havingexposed front and back surfaces. That is, the front and back surfaces ofthe glass film (2) are held in direct contact with the protective sheet(3). Note that, it is preferred that the front and back surfaces of theglass film (2) be not polished.

Silicate glass is used as the glass film (2). Preferably, silica glassor borosilicate glass is used, and most preferably, non-alkali glass isused. When the glass film (2) contains an alkali component, cationsubstitution occurs on the surfaces, and a phenomenon, so-called whiteweathering, occurs. As a result, the glass film is structurally rough.In this case, when the glass film (2) is used in a curved state, thereis a risk in that the glass film is prone to break from a portion thatis weathered over time. Note that, herein, the non-alkali glass includesglass that does not substantially contain an alkali metal oxide,specifically, glass containing an alkali metal oxide of 1000 ppm orless. In the present invention, as the alkali component, the glass filmcontains preferably the alkali metal oxide of 500 ppm or less, and morepreferably the alkali metal oxide of 300 ppm or less.

The glass film (2) is allowed to be wound, and hence is suitableparticularly for a long product. That is, a length (long side) of theglass film (2) is preferably 3 times or more, more preferably 5 times ormore, and still more preferably 10 times or more longer than a width(short side) of the glass film. Even when the glass film is such a longproduct, the glass film allows compact package, which is suitable intransportation. The width of the glass film (2) is 12.5 mm or more, andis selected as needed depending on a size of a substrate of a device tobe used, such as a small-screen display for a mobile phone or alarge-screen display. However, the width of the glass film is preferably100 mm or more, more preferably 300 mm or more, and still morepreferably 500 mm or more.

A thickness of the glass film (2) is more preferably 1 μm to 200 μm, andmost preferably 10 μm to 100 μm. The reason is as follows. When theglass film (2) has the thickness described above, it is possible toimpart appropriate flexibility to the glass film (2), to alleviateoverstress applied to the glass film (2) when winding the glass film(2), and to prevent the glass film (2) from breaking. In a case wherethe thickness of the glass film is less than 1 μm, strength of the glassfilm (2) is unsatisfactory. In a case where the thickness of the glassfilm exceeds 200 μm, there is increased a risk in that the glass filmmay break due to tensile stress when the glass film (2) is wound into aroll with a small diameter. Therefore, both cases are not preferred.

An arithmetic average roughness Ra of each end surface in a widthdirection of the glass film (2) is preferably 0.1 μm or less, and morepreferably 0.05 μm or less. This is because it is possible to impartappropriate smoothness to the each end surface in the width direction ofthe glass film (2). Therefore, in this case, when the glass film (2) iswound into a roll, small flaws are less likely to occur on the each endsurface of the glass film (2), and hence it is possible to wind theglass film (2) without any trouble. Further, it is possible to reduceglass powder, which is generated due to a chip and the like resultingfrom the small flaws on the end surface of the glass film (2), and hencethere is an advantage in ensuring cleanness of the front and backsurfaces of the glass film (2). In addition, even in a case where theend surface of the glass film (2) is held in contact with the protectivesheet (3), the end surface of the glass film (2) does not bite into theprotective sheet (3), and the glass film and the protective sheet can beseparated from each other easily. Consequently, prevention of breakageof the glass film (2) is achieved.

When the scribe line is formed in a surface of the glass film (2) alonga length direction with use of a diamond cutter or the like, and thenbend-breaking is performed, it is preferred that the glass film (2) bewound so that the surface with the scribe line is situated on an innercircumferential side. The reason is as follows. Small flaws occur on agroove of the scribe line thus formed, and hence, when the glass film(2) is wound so that the surface with the scribe line is situated on anouter circumferential side, the glass film (2) may break due to thetensile stress from the small flaws on the groove of the scribe line asan origin of breakage. However, in a case where, due to thermal stressthat is generated through expansion caused by a heat source such aslaser and through contraction caused by a refrigerant, an initial crackdevelops and then the glass film (2) is split, that is, in a case wherethe glass film (2) is cut by a method in which no small flaws occur oncut surfaces basically, a winding direction of the glass film (2) is notlimited. Further, by performing bend-breaking after formation of thescribe line and then performing fire polishing and chemical polishing,it is possible to process the end surface of the glass film (2).

When winding the glass film (2), stress is concentrated on the endsurface of the glass film (2) so that the glass film may break.Therefore, it is preferred that the end surface portion of the glassfilm (2) be protected with a resin film or the like. In this case, theglass roll (1) is produced by superposing the resin film on the glassfilm (2) in a region within 1 to 2 cm from the each end surface of theglass film (2) and winding the resin film and the glass film. Further,in a case of using an adhesive resin film, even when a crack occurs inthe end surface of the glass film (2), it is possible to preventdevelopment of the crack.

In a case where the glass film (2) is pulled out of the glass roll (1),and then the glass film (2) is supplied to various steps as processingsteps, when the glass film (2) is supplied to the steps while beingdirectly held, a leading end portion of the glass film (2) may break dueto contact with a member of the device. Therefore, it is preferred thatthe resin film be attached at the time of start of winding of the glassfilm (2) (leading end) and at the time of end of winding (trailing end).The resin film is less likely to break than the glass film (2), andhence the glass film can be supplied to the steps while the resin filmis held. As a result, it is possible to facilitate the supply to thesteps. The resin film is superposed and attached onto each of theleading end portion and the trailing end portion of the glass film (2)in the attaching region within approximately 1 to 2 cm from each of theleading end portion and the trailing end portion, and then winding isperformed so that the glass roll (1) is obtained. A length of the resinfilm is not particularly limited. For example, the length of the resinfilm may be set to correspond to a length of a contour of the glass roll(1). Further, it is preferred that the resin film have adhesiveness andan elastic modulus smaller than that of the glass film (2).

The glass film (2) is manufactured using the manufacturing deviceillustrated in FIG. 2. Just after flowing from a lower end portion (41)of a forming trough (4) with a wedge-shaped cross-section, a glassribbon (G) is drawn downward by cooling rollers (5) while beingrestricted from contracting in the width direction, to thereby bethinned to have a predetermined thickness. Next, the glass ribbon (G)having the above-mentioned predetermined thickness is gradually cooledby a lehr (annealer), and thermal strain of the glass ribbon (G) issubtracted. In this way, the glass film (2) is formed.

In the present invention, it is preferred that the glass film (2) beformed by the overflow downdraw method, as illustrated in FIG. 2 andFIG. 5. The reason is as follows. The overflow downdraw method is aforming method in which both surfaces of a glass plate are not held incontact with a forming member during forming, and hence flaws are lesslikely to occur on the both surfaces (translucent surfaces) of theobtained glass plate, and high surface quality can be obtained withoutpolishing.

When winding the glass film (2), the protective sheet (3) preventsoccurrence of the flaws, which is caused by contact of one part of theglass film (2) with another, and the protective sheet is used forabsorbing external pressure when the external pressure is applied to theglass roll (1). Therefore, it is preferred that a thickness of theprotective sheet (3) be from 10 μm to 2000 μm. In a case where thethickness is less than 10 μm, cushioning performance of the protectivesheet is unsatisfactory. In a case where the thickness exceeds 2000 μm,there is extremely increased a roll outer diameter of the glass rollformed after winding the glass film (2). Therefore, the both cases arenot preferred.

When producing the glass roll (1) according to the present invention, atemperature of the glass film (2) may exceed 50° C. Thus, it ispreferred that the protective sheet (3) be not transformed, for example,softened at a temperature of about 100° C.

It is preferred that the protective sheet (3) be slightly larger thanthe glass film (2) in the width direction. That is, it is preferredthat, in a state of the glass roll (1), the protective sheet (3) extendbeyond both sides in the width direction of the glass film (2). Thereason is as follows. With this configuration, each end surface in thewidth direction of the glass film (2) is protected with the protectivesheet (3), and hence it is possible to prevent small flaws and chips dueto impact or the like from occurring on the each end surface in thewidth direction of the glass film (2).

As the protective sheet (3), there can be used an ionomer film, apolyethylene film, a polypropylene film, a polyvinyl chloride film, apolyvinylidene chloride film, a polyvinyl alcohol film, a polypropylenefilm, a polyester film, a polycarbonate film, a polystyrene film, apolyacrylonitrile film, an ethylene vinyl acetate copolymer film, anethylene-vinyl alcohol copolymer film, an ethylene-methacrylatecopolymer film, a polyamide resin film (nylon film), a polyimide resinfilm, a buffer made of a resin such as cellophane, an inserting paper,and a nonwoven fabric. It is preferred that a polyethylene foam sheet beused as the protective sheet (3), because the polyethylene foam sheetcan absorb impact, and has high strength with respect to tensile stress.Meanwhile, when silica or the like is dispersed in those resin films sothat a degree of slip on the glass film (2) is increased, the slip canpreferably absorb a difference of lengths to be wound, which resultsfrom a slight difference of diameters caused when the glass film (2) andthe protective sheet (3) are wound while being superposed on each other.

The glass roll (1) may be formed by winding the glass film (2) so thatthe protective sheet (3) is situated on the outer circumferential side,or by winding the glass film (2) so that the protective sheet (3) issituated on the inner circumferential side. In the case of winding theglass film (2) so that the protective sheet (3) is situated on the innercircumferential side, winding is started after sticking the glass film(2) on the protective sheet (3) with a tape or the like, or after, asillustrated in FIG. 3, holding the glass film (2) and the protectivesheet (3) in a superposed state in a holding groove (68) provided in theroll core (6), or holding only the glass film (2).

It is preferred that conductivity be imparted to the protective sheet(3). This is because, when the glass film (2) is taken out of the glassroll (1), peeling electrification is less likely to occur between theglass film (2) and the protective sheet (3) so that the glass film (2)and the protective sheet (3) can be easily peeled off. Specifically, forexample, in a case where the protective sheet (3) is made of a resin, itis possible to impart the conductivity by adding a component forimparting the conductivity, such as polyethylene glycol, into theprotective sheet (3). In a case where the protective sheet (3) is madeof inserting paper, it is possible to impart the conductivity by addingconductive fiber. Further, it is possible to impart the conductivityalso by laminating a conductive layer, such as an indium-tin-oxide (ITO)film, on a surface of the protective sheet (3).

It is preferred that the glass roll (1) according to the presentinvention be wound around the roll core (6). In this way, the glass film(2) can be fixed onto the roll core (6) when being wound, and hence itis possible to wind the glass film (2) more firmly. Further, even whenthe external pressure is applied to the glass roll (1) obtained bywinding the glass film (2), the glass film (2) is not bent inward owingto the roll core (6). Accordingly, it is possible to prevent applicationof extreme tensile stress onto the glass film (2), and to preventbreakage of the glass film (2) more reliably.

It is preferred that a length of the roll core (6) be longer than awidth of the glass film (2). This is because it is possible to protrudethe roll core (6) from side edge portions of the glass roll (1), and toprevent small flaws and chips due to impact or the like from occurringon side edge portions of the glass film (2).

As a material of the roll core (6), there can be used metals such as analuminum alloy, a stainless steel, a manganese steel, and a carbonsteel, thermosetting resins such as a phenolic resin, a urea resin, amelamine resin, an unsaturated polyester resin, an epoxy resin,polyurethane, and a diallyl terephthalate resin, thermoplastic resinssuch as polyethylene, polypropylene, polystyrene, an AS resin, an ABSresin, a methacrylate resin, and vinyl chloride, reinforced plasticsobtained by mixing those thermosetting resins or thermoplastic resinswith reinforcement fibers such as a glass fiber or a carbon fiber, andpaper cores. Of the above-mentioned materials, aluminum alloy andreinforced plastic are excellent in strength, and paper allows areduction in weight. Thus, the two materials can be preferably used. Inaddition, it is preferred that the protective sheet (3) be wound one ormore turns around the roll core (6) in advance in order to preventoccurrence of flaws on a surface of the glass film (2).

At the time of start of winding the glass film (2) around the roll core(6), it is difficult to wind the end portion to be wound first of theglass film (2) along the roll core (6). If winding forcibly, overstressis applied to the end portion to be wound first of the glass film (2) sothat the glass film may break. Therefore, it is preferred that, asillustrated in FIG. 3, the roll core (6) be provided with the holdinggroove (68) for holding the end portion of the glass film (2). In thiscase, except in a case where winding of the glass film (2) is startedafter inserting the glass film and the protective sheet in the holdinggroove (68) simultaneously while the end portion of the glass film (2)is covered with the folded protective sheet (3) as illustrated in FIG.3( a), in a case where the holding groove (68) is made of a cushioningmaterial (69) as illustrated in FIG. 3( b), the winding can be startedafter inserting only the glass film (2).

It is more preferred that the roll core (6) be removed from the glassroll (1) according to the present invention after the glass film iswound around the roll core (6). The reason is as follows. That is, theroll core (6) is removed after the glass film (2) is fixed on the rollcore (6) once at the time when the glass film (2) is wound to be formedinto the glass roll (1) that is more firmly wound. Thus, it is possibleto achieve a reduction in weight of the glass roll (1), and to obtainthe glass roll (1) more suitable for transportation.

In the case of removing the roll core (6), as illustrated in FIG. 4, itis preferred to use the roll core (6) including an inner cylinder (65)and the outer cylinder (66), which serve as coaxial sleeves having adouble-circle shape, and including elastic members (67) interposedbetween the inner cylinder (65) and the outer cylinder (66). The reasonis as follows. When pressing the outer cylinder (66) in a centerdirection, the elastic members (67) contract so that the outer cylinder(66) is reduced in diameter. Consequently, it is possible to easilyremove the roll core (6) from the glass roll (1). In FIG. 4, the elasticmembers (67) are used as members for causing the outer cylinder (66) toexpand and contract. However, it is possible to adopt a configuration inwhich a space within the inner cylinder (65) and the outer cylinder (66)is sealed and the outer cylinder (66) is caused to expand and contractby changing fluid pressure in the internal space.

Tensile stress generated on a surface of the glass film (2) when theglass film (2) is wound to be formed into the glass roll (1) isdetermined by Equation 1 below.

$\begin{matrix}{\sigma = \frac{E \times \frac{T}{2}}{R + \frac{T}{2}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Note that, in Equation 1, σ represents a tensile stress value of anouter surface of the glass film, R represents a radius of an innerdiameter of the glass roll (radius of an outer diameter of the rollcore), T represents a thickness of the glass film, and E represents aYoung's modulus of the glass film.

Therefore, the radius R of the inner diameter of the glass roll (1)(radius of the roll core (6)) is determined by Equation 2 below.

$\begin{matrix}{R = {\frac{T}{2}\left( {\frac{E}{\sigma} - 1} \right)}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

Note that, in Equation 2, G represents the tensile stress value of theouter surface of the glass film, R represents the radius of the innerdiameter of the glass roll (radius of the outer diameter of the rollcore), T represents the thickness of the glass film, and E representsthe Young's modulus of the glass film.

By setting the radius R of the inner diameter of the glass roll (1) tobe equal to or larger than a value of the radius determined by Equation2 described above, it is possible to more appropriately select a windingradius at the time of winding of the glass film (2). Thus, the extremetensile stress, which results from an extremely small winding radius,can be prevented from being applied on the outer surface of the glassfilm (2). Consequently, it is possible to more reliably prevent breakageof the glass film (2). Note that, in the case of using the roll core(6), the radius of the outer diameter of the roll core (6) may be set tobe equal to or larger than the value determined by Equation 2 describedabove. For example, in a case of winding a glass film with a thicknessof 300 μm, when tensile stress generated on a surface of a glasssubstrate is about 27 MPa, the glass film can be wound around a rollcore with a diameter of 1 m.

The glass roll (1) according to the present invention is manufacturedusing the manufacturing device illustrated in FIG. 5. In the glass film(2) formed by the overflow downdraw method (for example, OA-10Gmanufactured by Nippon Electric Glass Co., Ltd.: thickness, 50 μm; andwidth, 150 mm), in order to eliminate roller contact portions which havebeen subjected to contact with the cooling rollers (5), disused portions(relatively thick portions) corresponding to the roller contact portionsat both end portions in the width direction of the glass ribbon (G) areeliminated by cutting means (7). As the cutting means (7), for example,means utilizing laser cutting is used. Here, as the laser cutting, meansfor laser fusing the glass film (2) can be used. However, in this case,the cut surface is fused by heat of laser irradiation, to thereby bethickened, which may cause a problem at the time of winding. In thiscontext, it is preferred to utilize, as the laser cutting, splittingmeans (hereinafter, referred to as laser splitting) using thermal stressgenerated by heat of laser irradiation. In the case of utilizing thelaser splitting, the glass film (2) is cut with use of the thermalstress generated by heat of laser irradiation, and hence it isunnecessary to heat the glass film (2) up to high temperature unlike inthe case of fusing. Therefore, there is no such defect that the cutsurface is fused to be thickened or extreme strain generates in theglass film (2) due to heat at the time of cutting. That is, it ispossible to more easily wind the glass film (2), and to more reliablyprevent breakage of the end portion. Further, the cut surface (splitsurface) by the laser splitting has a smooth cross-section with highstrength, and hence the arithmetic average roughness Ra of each endsurface in the width direction of the glass film (2) is 0.1 μm or lessas described above without being subjected to post-processing such aspolishing.

In the laser splitting utilized in this embodiment, as illustrated inFIG. 6, an initial crack (W) is formed in an end portion on a downstreamside of the glass film (2), and, after scanning the glass film along alongitudinal direction of the glass film (2) with a heating point (X) oflaser irradiation, the heated portion is cooled while scanning the glassfilm with a cooling point (Y) of a refrigerant, to thereby form a splitline (Z) while causing the initial crack (W) to develop due to thethermal stress generated by heating and cooling. Here, the split line(Z) is formed continuously from a front surface up to a back surface ofthe glass film (2). Therefore, at the point in time when the split line(Z) is formed by developing the initial crack (W) thereby, there is cuta disused portion corresponding to the portion in which the split line(Z) is formed. Note that, under a state in which the heating point (X)of the laser and the cooling point (Y) of the refrigerant are fixed,scanning with the heating point (X) of the laser and the cooling point(Y) of the refrigerant is performed by sequentially conveying the glassfilm (2) to a downstream side in a conveying direction (left directionin the example illustrated in FIG. 5).

In this embodiment, as illustrated in FIG. 5, under a state in which theglass film (2) is curved from an upright posture into a laid posture,the disused portions at the both end portions in the width direction ofthe glass film (2) are eliminated by the cutting means (7). Then, theglass film (2), from which the disused portions are eliminated, is woundaround the roll core (6) arranged at a position shifted laterally from aposition directly below a forming section. Specifically, the formingsection includes a forming zone (A), an annealing zone (annealer) (B),and a cooling zone (C). Then, an angle θ formed by a tangent line L1along the glass film (2) drawn out of the cooling zone (C) included inthe forming section, and a tangent line L2 along the glass film (2) at acontact point P between the roll core (6) and the glass film (2) is 90degrees or more, and the glass film (2) drawn out of the cooling zone(C) is smoothly curved along the two tangent lines L1 and L2 while beingsupported by support rollers (51) from below. With this configuration,an improvement of workability is achieved by changing the posture of theglass film (2) while preventing an action of overstress onto the curvedportion of the glass film (2). Note that, in this embodiment, the glassfilm (2) is curved to be inscribed in the tangent lines L1 and L2.

In this case, the protective sheet (3) is pulled out of a protectivesheet roll (31) provided below the roll core (6), and the protectivesheet (3) is superposed on an outer circumferential side of the glassfilm (2). Then, along the surface of the roll core (6), the glass film(2) and the protective sheet (3) are wound into a roll. In this way,after the glass film (2) is wound so as to have a predetermined rollouter diameter, a scribe is formed in the width direction of the glassfilm (2) with use of a width-direction cutter (not shown), andbend-breaking is performed. In this way, only the glass film (2) is cut.Then, after a trailing end of the cut glass film (2) is wound, theprotective sheet (3) is further wound one or more turns in this state,and the protective sheet (3) is cut. Consequently, manufacturing of theglass roll (1) according to the present invention is completed. In thiscase, an outermost layer of the glass roll (1) is constituted by theprotective sheet (3). However, in view of protection of the glass film(2), it is preferred that the protective sheet (3) be wound around theroll core (6) in advance and an innermost layer of the glass roll (1) bealso constituted by the protective sheet (3).

Note that, as described above, in the case where the protective sheet(3) is superposed on the outer circumferential side of the glass film(2), and then the glass film (2) and the protective sheet (3) are wound,the glass film (2) and the protective sheet (3) may be simultaneouslycut at a stage of having the predetermined roll outer diameter. In otherwords, winding is performed so that the protective sheet (3) is alwayssituated on the outer circumferential side of the glass film (2), andhence the outermost layer of the glass roll (1) can be constituted bythe protective sheet (3) without winding only the protective sheet (3)additionally.

Further, under a state in which the protective sheet (3) is superposedon the inner circumferential side of the glass film (2), the glass film(2) and the protective sheet (3) may be wound into a roll. In this case,it is preferred that, at the stage of having the predetermined rollouter diameter, after cutting only the glass film (2) in the widthdirection and winding the trailing end of the cut glass film, theprotective sheet (3) be further wound one or more turns as it is and theprotective sheet (3) be cut.

The glass film (2) is rich in flexibility due to its thinness. Thus, itis difficult to bend-break the glass film in the width direction by anordinary method, and hence it is preferred to bend-break the glass filmin the width direction by a method illustrated in FIG. 7. After thescribe line (75) is formed in the width direction by the width-directioncutter (74), the glass film (2) is conveyed as it is, and the scribeline (75) passes the pre-cutting rollers (71) as illustrated in FIG. 7(a). Then, as illustrated in FIG. 7( b), rotation speed of thepost-cutting rollers (73) and winding speed of the glass roll (1) areslowed relative to rotation speed of the pre-cutting rollers (71), and acutting roller (72) is lifted up from a conveyance line by drive means(not shown). As a result, the portion with the scribe line (75) of theglass film (2) subjected to bending is raised upward and bent, and thebend-breaking is performed through concentration of stress generated atthis time. Then, the cutting roller (72) is lowered, and the windingspeed of the glass roll (1) is increased after the post-cutting endportion passes the post-cutting rollers (73) as illustrated in FIG. 7(c). Thus, the glass roll (1) and the roll core (6) are replacedsimultaneously with completion of the winding, and then the processingis sequentially performed. Note that, cutting of the glass film (2) inthe width direction may be also performed utilizing the above-mentionedlaser splitting.

In the above description, description is made of the case where thelaser splitting is utilized as the cutting means (7). In this case, incomparison with a case where the scribe line is formed with a diamondcutter to perform the bend-breaking, it is possible to largely reducegeneration of glass powder. Moreover, small flaws such as micro crackscan be prevented from occurring in a cut end surface, and hence it ispossible to increase resistance due to tensile stress. For example, inthe case of using the diamond cutter, a value of an inner diameter (S)of the glass roll (1) (diameter of the roll core) is determined withreference to a value of σ of 30 to 60 MPa in Equation 2 described above.Meanwhile, in the case of using the laser splitting, even when the valueof the inner diameter (S) of the glass roll (1) (diameter of the rollcore) is set with reference to the value of σ of 220 MPa, it is possibleto produce the glass roll (1) without any problem. However, in a casewhere the glass film (2) is formed of molten glass, when taking intoconsideration that tensile stress resulting from strain at the time ofcooling is added to an end surface of the glass film besides tensilestress resulting from shape, it is safe to set the above-mentioned valueof σ up to 30 MPa.

At this time, a specific Young's modulus of the glass film (2) ispreferably 29 or more and 40 or less, and more preferably 29 or more and35 or less. The specific Young's modulus is obtained by dividing aYoung's modulus by specific gravity, and is used as a scale by which anamount of bending under self-weight is measured. The glass film (2) issubjected to sequential processing using a roll-to-roll method, and iscut into a predetermined dimension at the final stage for use. At thistime, the cut plate glass has high flexibility due to its thinness.Thus, when the glass film has the specific Young's modulus of less than29, the glass film is bent more than necessary in a post-cutting step sothat a trouble in the step may be induced. Therefore, the glass film isrequired to have a predetermined specific Young's modulus. Meanwhile,when the specific Young's modulus of the glass film exceeds 40, theglass film (2) is less likely to be bent, and hence it is difficult toform the glass roll (1).

Further, FIG. 5 illustrates a mode in which the protective sheet roll(31) is arranged below the glass film (2), and the protective sheet (3)is pulled out upward. However, there may be adopted a mode in which theprotective sheet roll (31) is arranged above the glass film (2), and theprotective sheet (3) is pulled out downward. Further, FIG. 5 illustratesa mode of winding the glass film (2) that is being conveyed in asubstantially horizontal direction. However, there may be adopted a modeof winding the glass film (2) that is being conveyed in a verticaldirection. In addition, in the above description, description is made ofthe case where the glass film (2) is formed by the overflow downdrawmethod. However, the glass film may be formed by a slot downdraw methodor a redraw method.

Note that, FIG. 5 illustrates a mode of winding a long product, in whichthe step from forming to winding are performed sequentially. In a caseof winding a short product, after the glass film (2) is cut into aplurality of pieces by a predetermined length in advance, the pluralityof cut glass films (2) may be wound by batch processing. Further, aplurality of short products may be wound into one glass roll (1).

FIG. 8 is a perspective view illustrating a mode of providing an outercovering body to the glass roll according to the present invention. FIG.9 is a perspective view illustrating a mode of providing a support barto the roll core of the glass roll according to the present invention.FIG. 10 is a perspective view illustrating a mode of providing flangesto the roll core of the glass roll according to the present invention.FIG. 11 is an explanatory diagram illustrating a method of placing theglass roll according to the present invention in a longitudinaldirection.

As a glass substrate for a display such as a liquid crystal display oran OLED display, there is required clean glass free from adhesion ofdust, dirt, and the like for its use. Therefore, as illustrated in FIG.8, a cylindrical outer covering body (8) is provided, and internal gasis replaced with clean gas. Consequently, a clean state can bemaintained. Further, a flat-plate-shaped lid body is swaged and fastenedto a cylinder body in a clean room, to thereby allow canning sealing. Inaddition, by packaging the glass roll (1) with a shrink film in theclean room, a clean state can be maintained.

When the glass roll (1) according to the present invention is placed ina lateral direction, because its weight is large particularly in thecase of a long product, the glass roll breaks from a placed surface sidedue to the self-weight. Therefore, in order to prevent the glass film(2) wound into the glass roll (1) from being held in direct contact withthe placed surface, it is preferred that, as illustrated in FIG. 9, ashaft (61) be provided to the roll core (6) and arranged on a pedestal(63) including bearings (62). In addition, it is preferred that, afterthe glass roll (1) is arranged on the pedestal (63), the entire glassroll be covered with a packaging box (not shown). This is because aclean state can be maintained by replacing the air inside the packagingbox with clean air. Every single glass roll (1) may be packaged in thepackaging box, or a plurality of glass rolls (1) may be packaged in onepackaging box together. In addition, by adopting a mode of taking theglass roll in and out of the packaging box in such a manner that thepedestal (63) is fixed in the packaging box and the shaft (61) of theglass roll (1) is hung by a crane or the like, the pedestal (63) isfirmly fixed in the packaging box during transportation, and henceexcellent safety is provided.

It is preferred that, as illustrated in FIG. 10, flanges (64) beprovided to both end portions of the roll core (6), respectively, so asto prevent the glass film (2) from being held in direct contact with theplaced surface. The reason is to prevent the glass film (2) wound intothe glass roll (1) from being held in direct contact with the placedsurface. Although the flanges illustrated in FIG. 10 have circularshapes, flanges having polygonal shapes can prevent the glass roll (1)from rolling when being placed on a floor surface. The flanges (64) maybe removably attached to the roll core (6). In this case, only the rollcore (6) is used at the time of winding and rewinding, and the flanges(64) for protecting the glass film (2) are attached duringtransportation and storage.

In a case where the glass film (3) is slid on the roll core (6) duringtransportation or the like, there is a risk in that an end surface ofthe glass film (2) comes into contact with the flange so that the glassfilm may break. Therefore, in the case of the mode of providing theflanges (64), it is preferred that a width of the protective sheet (3)be larger than a width of the glass film (2). The reason is as follows.When the width of the protective sheet (3) is large, even if the glassfilm (2) is slid on the roll core (6), the end surface does not comeinto direct contact with the flange (64), and hence it is possible toprevent breakage of the glass film (2). Note that, it is preferred thatinner surfaces of the flanges (64) be also protected with members havinga cushioning action.

As described above, when the glass roll (1) according to the presentinvention is placed in the lateral direction, the glass roll breaks dueto its self-weight. Therefore, in order to prevent the glass film (2)wound into the glass roll (1) from being held in direct contact with theplaced surface, it is preferred that the glass roll (1) be placed in thelongitudinal direction using a packaging device (9) illustrated in FIG.11. The packaging device (9) includes a base portion (91) and columnarportions (92) provided upright on the base portion (91). As illustratedin FIG. 11, the glass roll (1) is placed on the base portion (91) in thelongitudinal direction so that each of the columnar portions (92) isinserted into the roll core (6) of the glass roll (1). In this way, evenif the glass roll (1) is shaken during transportation, the glass roll(1) is fixed by each of the columnar portions (92), and hence it ispossible to prevent breakage of the glass film (2), which results fromimpact of the glass roll on another glass roll. It is preferred that thecolumnar portions (92) be removably attached to the base portion (91).Removable attachment can facilitate loading and unloading of the glassroll (1). The columnar portions (92) are provided upright with intervalslarge enough to prevent the impact of the glass roll (1) on anotherglass roll when the glass roll (1) is placed. In order to preventshaking during transportation, a cushioning material may be filledbetween the glass rolls (1). It is preferred that the base portion (91)be provided with a hole for a forklift. Further, with provision of a boxbody (not shown), tight package is possible.

FIG. 12 is a view illustrating a processing method for the glass rollaccording to the present invention. FIG. 13 is a view illustratinganother processing method for the glass roll according to the presentinvention. FIG. 14 is a view of the protective sheet having a surfacesubjected to embossing.

When performing processing, such as cleaning and drying, on a glasssubstrate, only one-by-one conveyance is possible for a conventionalrectangular glass substrate. However, the glass roll (1) according tothe present invention can be subjected to sequential processing usingthe roll-to-roll method. For example, by a method illustrated in FIG.12, it is possible to perform sequential processing, i.e., a cleaningstep (110), a drying step (111), and an antistatic step (112), using theroll-to-roll method. The glass film (2) has flexibility, and hence it ispossible to soak the glass roll in a cleaning tank in the cleaning step(110). When the glass roll (1) according to the present invention issubjected to sequential processing using the roll-to-roll method, it ispreferred that, as illustrated in FIG. 13, the sequential processing beperformed under a state in which the glass roll (1) is placed upright.The glass film (2) has rigidity higher than that of the resin film, andhence the roll-to-roll method can be implemented under a state in whichthe glass roll is placed upright. When the roll-to-roll method isimplemented under the upright state, satisfactory drainage is achievedafter the completion of the cleaning step, and conveying rollers (113)and a surface of the glass film (2) are not held in contact with eachother. Thus, it is possible to more reliably prevent occurrence offlaws. Note that, in the processing method illustrated in FIG. 13, whenthe glass film (2) flutters, an upper portion of the glass film (2) maybe supported by a conveying roller (not shown) provided as needed.

At this time, when using the glass roll (1), which is not driedsufficiently after the cleaning, in a step in which moisture is to beexcluded strictly, it is necessary to exclude moisture adhering to asurface of glass before using the glass roll, and hence it is necessaryto dry the glass roll (1) in a roll state sufficiently before the glassroll (1) is introduced into the step. In this case, as illustrated inFIG. 14, it is preferred to use the protective sheet (3) having asurface with asperities, which is subjected to embossing or the like.The reason is as follows. A surface of the protective sheet (3) is notentirely held in contact with the glass film (2), and hence theprotective sheet is excellent in breathability and allows fast drying ofthe glass film (2). Further, it is preferred that the roll core (6) havea structure excellent in breathability with provision of a hole, a slit,or a mesh. In addition, it is preferred that a heater be arranged on ahollow portion of the roll core (6) and drying be performed by heatingfrom an inside of the roll core (6). After the drying, the glass roll(1) is sealed, for example, in the outer covering body illustrated inFIG. 8, and a desiccant or the like is put inside the outer coveringbody. In this way, the dried state can be maintained. Further, an endsurface of the glass roll (1) can be provided with a sheet-likedesiccant (for example, sheet containing silica gel), and be coveredwith a moisture-proof film (such as metal layer deposited film).

INDUSTRIAL APPLICABILITY

The present invention can be preferably used to a glass substrate of adevice used for a flat panel display, such as a liquid crystal displayor an OLED display, and for such as a solar cell, and used to coverglass for an OLED lighting.

REFERENCE SIGNS LIST

-   -   1 glass roll    -   2 glass film    -   3 protective sheet    -   4 forming trough    -   6 roll core

The invention claimed is:
 1. A manufacturing method for a glass roll,the method comprising: forming a glass film by a downdraw method;winding the glass film into a roll using a winding roller in a state inwhich front and back glass surfaces of the glass film formed in saidforming operation are exposed; and during said winding operation,superposing the glass film on a separable protective sheet, wherein theprotective sheet extends beyond both sides of the glass film in a widthdirection of the glass film, and wherein the protective sheet is woundone or more turns around the winding roller before said winding theglass film around the winding roller.
 2. The manufacturing method ofclaim 1, further comprising laser cutting a disused portion before saidwinding operation, wherein the disused portion is disposed on each endportion of the glass film in the width direction of the glass film. 3.The manufacturing method of claim 1, wherein said winding operation isperformed in a state in which the protective sheet is arranged on thewinding roller side relative to the glass film, and wherein the methodfurther comprises, after said winding operation, winding the protectivesheet on an outer peripheral surface of the glass film by winding onlythe protective sheet from a trailing end of the glass film in a windingdirection of the glass film.
 4. The manufacturing method of claim 1,wherein said winding operation is performed in a state in which theprotective sheet is arranged on the winding roller side relative to theglass film, wherein the method further comprises: cutting a trailing endof the glass film and continuing said winding operation until thetrailing end is wound on the winding roller; and after the trailing endof the glass film has been wound on the winding roller, winding theprotective sheet on an outer peripheral surface of the glass film bywinding only the protective sheet.
 5. The manufacturing method of claim1, further comprising winding the glass film and the protective sheetunder a state in which the glass film is arranged on the winding rollerside relative to the protective sheet.
 6. The manufacturing method ofclaim 1, wherein the downdraw method includes an overflow downdrawmethod and a redraw method.
 7. The manufacturing method of claim 1,wherein the glass film has a thickness of 1 μm or more and 200 μm orless.
 8. The manufacturing method of claim 1, wherein each end surfacein a width direction of the glass film has an arithmetic averageroughness Ra of 0.1 μm or less.
 9. The manufacturing method of claim 1,wherein the protective sheet is a resin sheet.
 10. The manufacturingmethod of claim 1, wherein said forming operation is performed in aforming section, wherein the winding roller is arranged at a positionshifted laterally from a position directly below the forming section,and wherein the glass film drawn out of the forming section is curvedand supplied to the winding roller arranged at the position shiftedlaterally.
 11. The manufacturing method of claim 1, wherein said formingoperation includes using cooling rollers to draw a glass ribbon from aforming trough to form the glass film, the forming trough being disposedin a forming section, wherein the winding roller is arranged at aposition shifted laterally from a position directly below the formingsection, and wherein the glass film drawn out of the forming section iscurved and supplied to the winding roller arranged at the positionshifted laterally using support rollers.
 12. The manufacturing method ofclaim 1, further comprising, after said winding operation, separatingthe protective sheet from the glass film.
 13. The manufacturing methodof claim 1, wherein the method further comprises winding the protectivesheet on an outer peripheral surface of the glass film one or more turnsby winding only the protective sheet from a trailing end of the glassfilm in a winding direction of the glass film.
 14. The manufacturingmethod of claim 1, wherein the glass film is arranged on an innercircumferential side of the protective sheet.
 15. The manufacturingmethod of claim 1, wherein the glass film is arranged on an outercircumferential side of the protective sheet.